1. Field of the Invention
This invention relates to pipe locating equipment and, more particularly, to plastic-pipe locating equipment.
2. Prior Art
In the 1950's many utilities, such as those providing gas for heating purposes, installed plastic pipes between the mains and the houses or buildings being serviced. In some cases, locating wires were provided along with the plastic pipes, but in many cases locating wires were not provided. With time, the plastic pipes became brittle and required, and still require, replacement. Such pipes are, of course, buried and connect with the mains well below the surface of the earth. With metal pipes, it is quite simple to trace the location of the pipe by means of magnetometer devices or by applying R.F. signals to the pipe and picking up the radiation from the pipe with a sensing device. With plastic pipes having no locator wires, conventional techniques are not applicable. It has been the practice, up to the time of this invention, to look for characteristic markings on the curbings, such markings having been applied by the individuals who installed the plastic pipes. Conventionally a "G" was marked on the curbing where the pipe, in this case a gas pipe, passed into the street headed toward the main gas pipe. Experience showed that the markings were not accurate and the workers were forced to dig numerous holes in an attempt to find the connection between the plastic pipe and the main pipe. The number of the installations of plastic pipes, particularly in the gas industry, was very large and the randomness of the "dig-and-hope" method originally applied, cost the gas companies large sums of money. It was found that, on the average, seventy minutes of time was wasted in trying to find the connection between the plastic pipe and the main pipe.
Therefore it is an object of this invention to overcome the disadvantages and problems of prior art methods for finding plastic pipes which are being used to carry fluids.
It is a further object of this invention to provide a tool which will assist in the finding, with the minimun expenditure of time and money, the location of plastic pipes being utilized to carry fluids such as heating gas.